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NANCY CLARK: Sports Nutrition News

The Athlete’s Kitchen

Copyright: Nancy Clark September 2013

More Sports Nutrition News You Can Use

The 2013 Annual Meeting of American College of Sports Medicine was chockful of nutrition news you can use. This article continues from where I left off in my previous article (June 2013) and offers additional research findings.

• Do serious athletes need protein supplements? Doubtful. Among 30 competitive 14- to 20-year old male and female athletes who were living at a sports training facility (IMG Academies), all of the males and 75% of the females consumed more than the recommended protein intake: about 0.5 to 0.75 g protein/lb (1.2 to 1.7 g pro/kg). The dietary assessments indicate they consumed about 1 g protein/lb (2 g pro/kg) via their standard daily meals and snacks.

• Although athletes can easily consume adequate protein from standard meals, a survey with 150 male and female Division-I collegiate athletes indicates more than half of them use protein supplements. A waste of money?

• Among 215 Navy SEALs, 86% ate less than the recommended carbohydrate intake (>5 g carb/kg). Like many serious athletes, the SEALs chose a diet that would help build muscles—but not optimally fuel muscles.

• Are commercial recovery drinks better than homemade ones? Doubtful. A study comparing a fruit smoothie (made with milk, banana, berries) with a commercial product showed similar recovery benefits for subjects who did muscle-damaging exercise. Both recovery drinks offered the same amount of calories, protein, and carb. Food works!

• Even experienced veteran cyclists do a poor job of refueling. Only 38% of 212 competitive cyclists chose a carbohydrate-protein mix. Because residual fatigue from both training and competition strongly influences the ability to perform optimally, you would be wise to pay attention to a proper recovery diet!

• Although adequate hydration contributes to optimal performance, it can disrupt sleep in athletes who rehydrate primarily at the end of the day. A study with 35 male rugby players indicates 75% of them did a good job of rehydrating at a 10-day training camp. However, those who hydrated well at night tended to wake up at least three or more times to urinate. For better sleep, drink more fluids right when you finish exercising, instead of near bedtime.

• For 17 days, well-trained cyclists took an antioxidant supplement containing freeze-dried fruit-vegetable juice powder. The supplement offered no boost in immune function beyond that created by exercise itself. Instead of antioxidant pills, you might want to buy a health club membership?

• Sprinters, rowers and other competitive athletes who do high intensity exercise sometimes use a buffer (such as beta-alanine or sodium bicarbonate) that delays the onset of fatigue associated with lactic acid. Athletes who use beta-alanine often complain about “beta-tingles,” a tingling and itchy side effect. The itchiness is not resolved by taking an antihistamine, because the response is activated by the nervous system, not the immune system. A solution is to choose time-released beta-alanine capsules.

• Would combining beta-alanine with sodium bicarbonate be more effective than either buffer alone at enhancing an athlete’s ability to perform intense exercise? Perhaps—but they would have to be able to tolerate the sodium bicarb. Rowers in a 2000-meter time trial experienced more benefit from the beta-alanine alone (6.5 seconds faster) vs. sodium bicarb alone (3 seconds faster). Both taken together added a 1-second bonus, enough to possibly be beneficial.

• Intestinal issues are a major problem among athletes. Among a group of 36 triathletes in the Lake Placid Ironman, 81% complained of stomach pain and cramping. Athletes who consumed either adequate or inadequate fluids both reported similar GI problems. The symptoms were generally mild and did not correlate with finish time.

• If you cannot tolerate pre-exercise food due to nerves (or are fasting, as happens with some religious holidays), try swishing with water or a sports drink. Either can help you perform better. Compared to cyclists who did not swish, those who rinsed their mouth with either regular or calorie-free sports drinks during a 30-minute warm-up performed about 4 minutes faster (13 vs. 17 min.) in a 10-K time trial.

• If you have ever broken a bone, you were likely dismayed when the cast was removed and you saw how much the muscle shrank. Muscles quickly lose size and strength within 5 days. In a study with young men (23 years old) who had a full-leg cast for 5 or 14 days, the size of the quadriceps decreased from baseline by 3.5% in 5 days and 8.5% in 14 days. Strength declined by 8.5% and 23% in 5 and 15 days, respectively. Use it or lose it.

• When 59-year-old adults lifted weights twice a week for 12 weeks, they lost only about 2 pounds of fat and gained only about 1 pound of muscle. The exercise program did not trigger any spontaneous dietary improvements. Take note: It’s hard to out-exercise a poor diet...

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• Some women fret that adding weight lifting to their cardio workouts will make them “bulk up.” Ten sedentary adults (ages 23-24) alternated days of high-intensity interval rowing with maximal-intensity weight lifting. In 5 weeks, the women had no significant changes in body composition. In comparison, the men added about 3.5% lean body mass (muscle). Ladies, little need to fret about bulking up!

• Having arthritis should not be an excuse to stop exercising. Exercise actually helps reduce the pain and fatigue associated with osteoarthritis and improves one's ability to sit/stand and walk.

• Being active offers more than health benefits. Office workers who were taught how to reduce sedentary behaviors perceived they improved their work performance. For certain, living an active lifestyle is the right choice!

Nancy Clark, MS, RD, CSSD (Board Certified Specialist in Sports Dietetics) counsels both casual and competitive athletes at her office in Newton, MA (617-795-1875). Her Sports Nutrition Guidebook and food guides for new runners, marathoners, and soccer players offer additional information. They are available at www.nancyclarkrd.com. For online education, see sportsnutritionworkshop.com.